Drive east toward one of the most visited villages in Cantabria — and the most honestly medieval town on this entire route.

Santillana del Mar is a village of cobblestone streets, stone palaces, and Romanesque architecture that has been preserved well enough to feel genuinely old rather than restored into sterility. The collegiate church at its center dates to the twelfth century. The manor houses lining the main street were built by noble families over several centuries and most are still standing in largely original condition.

It is also, particularly in summer, busy. The village is small and the main street is the only street — which means the crowds concentrate and the atmosphere can tip from historic to theme park depending on when you arrive.

Go early in the morning or late in the afternoon when the day trip coaches have left. The village at those hours — light on the stone, almost no one on the street — is a different experience from the midday version.

Practical note: the Altamira cave paintings are nearby. The original cave is closed to the public to preserve the paintings but a full-scale replica — the Neocueva — is open and genuinely impressive as a reproduction. Worth thirty minutes if you have them. Worth knowing about even if you skip it.